dangerous ideas: evolution jeremy pritchard school of biosciences
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Dangerous ideas: Evolution
Jeremy PritchardSchool of Biosciences
Cratægus oxycantha.—A dark pink hawthorn has been known to throw out a single tuft of pure white blossoms;18
Mr. A. Clapham, nurseryman, of Bradford, informs me that his father had a deep crimson thorn grafted on a white thorn, which, during several years, always bore, high above the graft, bunches of white, pink, and deep crimson flowers.
Darwin was staying in Ilkley and taking water cure treatments when ‘On the Origin of Species…’ was published in November
1859
Hillside Court, Ilkley White Wells Bath House, Ilkley Moor
http://www.biosciences.bham.ac.uk/links/teachers/teachers.htm
o Many are born o Individuals vary o Not all survive o ‘Useful’ variations
increaseo Variations are inherited
Darwin’s theory of evolution
Diversity is the consequence of the non-random survival of randomly varying replicators
1. Random = Mutation
2. Non random = Natural selection
3. Replicators = Inheritance
Evolution was one of the first Darwin beers produced.
The strange thing was that a mistake was made on the original recipe
-yet the resulting beer was (and still is) better than we could have imagined..
-hence the beer evolved into one of our best sellers.
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Biology
English
Engineering
Support evolution Don’t support Evolution
# students
Subject specific views of evolution:
2nd year students University of Birmingham,
Autumn 2007
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Definitelytrue?
Probablytrue?
Probablyuntrue?
Definitelyuntrue?
Don't know?
Young Earth Creationism is the idea that God created the world sometime in the last 10,000 years.In your opinion is Young Earth Creationism…
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True False
“The diversity of organisms, similarities and differences between kinds of organisms, patterns of distribution and behaviour, adaptation and interaction, all this was merely a bewildering chaos of facts until given meaning by the evolutionary theory.”Mayr
“Science simply cannot … adjudicate the issue of God’spossible superintendence of nature. We neither affirm nor deny it; we simply can’t comment on it as scientists.”
Gould
The issues
o Organising diversity - treeso Evolution as ‘dangerous’o Design and complexity from chanceo Science and intelligent design
10s of years
100s of years
1000s of years
Millions of years
There is a lot of diversity out there…
Where does it come from?
Organising diversity:
Taxonomy and trees
So…..
What’s the reason some things are more similar than others?
Descent with modification from a common ancestor
What’s the mechanism?
Natural selection
The issues
o Organising diversity - treeso Evolution as ‘dangerous’o Design and complexity from chanceo Science and intelligent design
o Fact ?o Mechanism ?
Change…
The Great Chain of Being
The Great Chain of Being
• Ideas of organisation and direction in evolution
• Complex is better
The middle ages
• Change is dangerous…
AL-BIRUNI 973 - 1048
• Gradual changes
• But change is dangerous…
Change…? Stasis!!
Classification - Linneaus
• Species descriptions
• But some things are more similar than others...
Explaining complexity
Intelligent design
• Explaining complexity
Irreducible Complexity = Intelligent design
Michael J. Behe
Is Intelligent Design a Science?
The emergence of change
Stasis ? …Change
Voyages of discovery
Wedgwood
• Small changes improve things
• Experiments are needed
But change is dangerous…
Erasmus Darwin
Stasis ?.... Change!
Mechanism?
•Inheritance of acquired characteristics
•Desire to improve
Lamark
Charles Darwin
Noted
1. Overproduction of young
2. Rising population outstrips resources
3. Lower classes are irresponsible.
Solution
Family size of the lower class regulated so that they do not produce more children than they can support
Malthus: An Essay on the Principle of Population
Replacement of religion ?
Who trusted God was love indeed And love Creation’s final law–
Tho’ Nature, red in tooth and claw With ravine, shriek’d against his creed–
o Evolution explains mechanism o It does not explain purpose
o Ask What? and How?
o Be careful with Why?
Replacement of religion?
Are we still evolving?Microevolution: change in gene frequency - YES
Macro evolution: formation of species - NO
Are we still evolving?
• Some parts of Africa have seen an increase in the frequency of a gene called CCR5-32
• Protects against infection with HIV-1.
• May have been selected for during bubonic plague
Human Chimp
H. erectus
H. habilis
A. afarensis
Monkey ancestor
Australopithecus afarensisLucy, 3 mya
Two legs good,
four legs bad?
•Bad back
•Flat feet
•Varicose veins
•Heart disease
•Piles
Humans are not top of the tree …
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1.A Historical perspective: One strategy for confronting creationist’s views is to take a historical perspective. Explaining how the theory of evolution by natural selection developed allows the teacher to take a more less
2.Human Evolution: A practical that explores human bipedalism and larger brain size. Measurements are performed on hominid fossil material and the students themselves. The necessary pictures needed to do the exercise can be downloaded.
3.Taxonomy: Phylogenetic trees provide a powerful image/metaphor to explain some important evolutionary concepts. Students choose phenotypic characters for a range of organisms and these are fed into a computer programme reveals the similarities and differences between the organisms. The practical can be delivered in a variety of ways, from the class room through to zoo visits.
4. Evolution in action: Variation, mutation and selection in plants: An experiment that demonstrates some of the components of evolution. Arabidopsis plants are grown in the presence or absence of sodium chloride and measurements of rate of development demonstrate both variation and the selective effect of stress.
5. Evolution of complexity: Evolution theory is often critisised for being unable to explain how chance can generate complex organs such as the eye. However Natural selection is a combination of random mutation and non-random differential survival. An 'Excel' exercise to demonstrate how complexity can be rapidly produced by chance plus selection is available.
6. Dealing directly with Creationist arguments: A creationist document arguing that plants cannot have evolved by Darwinian evolution has been annotated with over 80 the counter arguments and can accessed online.